1. Field of the invention:
This invention relates to a multi-terminal semiconductor laser device which attains laser oscillation with a stabilized oscillation wavelength and which allows changes in the oscillation wavelength.
2. Description of the prior art:
With enlarged-applications in such fields as optical communication systems, optical-measuring systems, optical information processing systems, semiconductor lasers, etc., semiconductor laser which oscillate laser light with a stabilized oscillation wavelength are required. In order to achieve an optical communication mode with wavelength superposition, frequency modulation (FM) or the like, semiconductor lasers allowing the oscillation wavelength to vary are also required. For these reasons, semiconductor lasers such as distributed feedback (DFB) lasers, distributed Bragg reflector (DBR) lasers, internal reflector interferometric lasers, compound resonator type lasers, external resonator type lasers, etc., have been studied. However, skilled workers are required for the formation of diffraction gratings of the DFB lasers and the DBR lasers. Moreover, structures and the production process of the internal reflector interferometric lasers, compound resonator type lasers, and external resonator type lasers are complicated, and it is difficult to put them into practical use.